Civil Engineering Reference
In-Depth Information
supplements to the deterministic approach. Probabilistic safety analyses begin with
the assessment of initiating events (malfunction and defects in plant components) as
well as external events like earthquakes etc.. Analyzing the sequence of events
requires exact knowledge of all safety systems of a nuclear power plant.
The results of a PSA are frequencies per reactor year for the failure of specific
components of the safety systems and for the occurrence of specific accident
sequences. In this way, weak spots in technical safety can be identified and the
engineered safeguards design of a nuclear power plant can be optimized. When
used in risk analyses, these values also serve for relative comparisons, e.g. between
various others energy systems.
The results of PSA show that the frequency of events gradually decreases from
safety level 1 to safety level 2 to safety level 3 to safety level 4. The calculated
occurrence of core meltdown upon failure of the safety systems lies beyond safety
level 4 in the range of a target of 10
5
to 10
6
per reactor year to be reached. The
results of probabilistic safety analyses are associated with uncertainties stemming
from uncertainties of the data, assumptions, and methods applied in various ways
[
4
,
5
,
7
-
9
].
5.5 Atomic Energy Act, Ordinances, Regulations
Most countries operating nuclear reactors or fuel cycle facilities issued an Atomic
Energy Act. The “Act on the Peaceful Uses of Nuclear Energy and the Protection
against Its Hazards” (Atomic Energy Act) establishes the legal frame for the
peaceful utilization of nuclear power.
The provisions of the Atomic Energy Act are supplemented by additional
ordinances (in case of Germany as an example), such as
- the Radiation Protection Ordinance,
- the Ordinance on Safety Commission and Reporting Duties under the Atomic
Energy Act,
- the Ordinance on Insurance Cover under the Atomic Energy Act.
In addition, there are regulations about technical safety which serve as a basis in
the licensing practice of the licensing and supervisory authorities, such as
- safety criteria and guidelines for the design of nuclear power plants,
- guidelines, e.g., about the specialized knowledge required for nuclear power
plant personnel.
